[RFC PATCH 2/2] acpi: video: Add force native backlight quirk for Lenovo Ideapad Z570

[Hans de Goede <hdegoede@redhat.com>]

The Lenovo Ideapad Z570 (which is an Acer in disguise like some other Ideapads)
has a broken acpi_video interface and is too old for the acpi-video code to
automatically prefer the native backlight interface, so add a quirk for it.

Note that this cannot be done with a quirk in the vendor backlight driver as
is the normal way to fix this as the Z570 offers both acer-wmi and
ideapad-laptop vendor backlight interfaces, so this would require the same
quirk in 2 places which is the wrong thing to do.

BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=1187004
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
 drivers/acpi/video.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c
index 9817b52..70a7ec3 100644
--- a/drivers/acpi/video.c
+++ b/drivers/acpi/video.c
@@ -419,6 +419,12 @@ static int __init video_disable_native_backlight(const struct dmi_system_id *d)
 	return 0;
 }
 
+static int __init video_force_native_backlight(const struct dmi_system_id *d)
+{
+	use_native_backlight_dmi = 2;
+	return 0;
+}
+
 static struct dmi_system_id video_dmi_table[] __initdata = {
 	/*
 	 * Broken _BQC workaround http://bugzilla.kernel.org/show_bug.cgi?id=13121
@@ -560,6 +566,17 @@ static struct dmi_system_id video_dmi_table[] __initdata = {
 		DMI_MATCH(DMI_PRODUCT_NAME, "XPS L521X"),
 		},
 	},
+
+	/* Non win8 machines which need native backlight nevertheless */
+	{
+	 /* https://bugzilla.redhat.com/show_bug.cgi?id=1187004 */
+	 .callback = video_force_native_backlight,
+	 .ident = "Lenovo Ideapad Z570",
+	 .matches = {
+		DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
+		DMI_MATCH(DMI_PRODUCT_NAME, "102434U"),
+		},
+	},
 	{}
 };
 
-- 
2.3.1